1. Field of the Invention
This invention relates to a chair having an ergonomic lumbar support air cushion therein in which the amount of air can be manually controlled so that a personalized amount of back support can be achieved and retained and yet is easily adjusted.
2. Description of the Prior Art
It is recognized that no one seat back shape or contour is ideal for all persons who will be occupying the seat and, as a result, it is of advantage to provide means for adjusting the seat back contour. Notably, the provision for the adjustment of a lumbar section in the seat back is very desirable. As a result, special support cushions have been developed for the lower portion of the back. Such lumbar support cushions, provided in the past, are both weight responsive and manually adjustable.
In one form of such adjustable lumbar cushion, an open-cell foam material is provided in an air-tight envelope. A push button form of manually-controllable valve is used in an air passageway to the interior of the envelope and the foam. Thus, where the cushion thickness is greater than desired by the seat occupant, the seat occupant can push his back against the cushion zone while at the same time opening the valve to let air out of the open-cell foam encased within the envelope. When the cushion has the right lesser thickness or feel, the occupant can close the valve and maintain a vacuum in the cushion envelope. On the other hand, if the occupant wishes to let the lumbar cushion have a greater thickness or a fuller support, the occupant can temporarily lean forward and take his back weight or pressure from the cushion while opening the valve so as to let the vacuum of the open-cell foam pull in ambient air. Nevertheless, problems of operation of the valve which was essential for the effective changing of the contour of such cushion necessitated improvements therein.
Accordingly, U.S. Pat. No. 3,652,126 patented Mar. 28, 1972 by N. D. Folling provided a pneumatic form of seat back panel adjustment system for a seating unit. Such seating unit included an air-tight seat envelope traversing a portion of the seat area of the seating unit. An open-cell foam filler having internal springiness and resilience was included to provide self-inflation and air storage therein. A movable seat back panel section traversed a portion of the back of the seating unit. An expansible-contractible bladder having a substantially smaller internal volume than the seat envelope was positioned in combination with the movable seat back panel section and was included to provide outward and return movements for such section. A conduit connected the bladder with the seat envelope. A manually-operative valve was provided in the conduit to permit air flow between the seat envelope and the bladder. An air inlet included a check valve connected to the interior of the seat envelope to the open-cell foam. Ambient air automatically flowed into the open-cell foam when there was no occupant weight thereon to replenish air transferred to the bladder.
U.S. Pat. No. 3,661,422 patented May 9, 1972 by J. Sember et al provided a valve for a weight responsive support cushion unit that was adapted for supporting a particular portion of the human body, where open-cell foam cushion material was maintained in an air-tight envelope. An ambient air passageway was provided to the envelope and a manually-controllable valve means was connected to the passageway to regulate the flow of ambient air pressure into and out of the envelope. The valve included a body member with an air-inlet-outlet to the interior thereof. A manually movable plug member included movement means connected thereto to permit air flow into and out from that body member through the inlet-outlet. A separate small area bleed-in orifice was provided to the interior of the valve body. A separate displaceable orifice covering was provided for the interior face of the bleed-in orifice. A vacuum condition in the envelope provided for an inward ambient air flow through the bleed-in orifice and the passageway. Conversely, a weight pressure on the envelope provided a back pressure and seating of the covering means over the orifice.
U.S. Pat. No. 3,770,315 patented Nov. 6, 1973 by D. C. Smittle et al provided an adjustable lumbar support for a chair having a seat portion and a resilient adjustable chair back. That lumbar support included a cavity in the chair back opposite the lumbar region of a chair occupant. The lumbar support was positioned in the cavity for engaging a chair occupant's lumbar region. The lumbar support included a flexible, impermeable envelope having one face in the cavity and the other face approximately complementary to a person's lumbar region. An open cell, elastically-resilient body of foam was situated in the envelope, the body of foam extending forwardly from the cavity beyond the adjacent chair back. Means were provided for controlling gas pressure within the envelope for adjusting the firmness of the lumbar support means. The control means were mounted on the chair in a position accessible to a chair occupant.
U.S. Pat. No. 4,832,401 patented May 23, 1989 by V. L. Brooks provided a lumbar support which had means for its connection with a femur seat cushion of a seat. The femur seat cushion was deflectable with respect to the seat cushion frame of the seat. The lumbar support was also slidably and resiliently mounted to the seat back. The location of the lumbar support with respect to the seat back was a function of the deflection of the femur seat cushion with respect to the seat cushion frame. Therefore, the lumbar support exhibited a tendency to be closer to the optimum position in relationship to seat occupant's back regardless of the seat occupant's weight.
U.S. Pat. No. 4,890,885 patented Jan. 2, 1990 by K. Grossman provided a seating arrangement including a seat, a backrest including a backrest frame and an integrated headrest. A vacuum cushion was arranged at the backrest within the area of the headrest. The vacuum cushion included a cover of air non-permeable material, and a large number of small plastic material parts arranged inside of the cover. An extraction pump and at least one valve were provided for individually matching the vacuum cushion to the physiological cervical spinal column-lordosis of the seat user.
U.S. Pat. No. 5,033,133 patented Jul. 23, 1991 by G. P. Nissen provided a seat cushion having an inner core of a compressible material having an open cellular structure filled with air when uncompressed. Compression of the material expelled air from that structure. The inner core had an uncompressed size and shape complementary to the seat cushion. An inner cover enclosed the inner core material, the inner cover being of an air-tight material and being sealed, thus hermetically sealing an inner space thereof including the inner core from the atmosphere. The inner cover was of a size larger than the uncompressed size of the inner core and fitted loosely about the inner core. An outer cover enclosed the inner core and inner cover and was of a size which was smaller than the size of the inner cover. The inner cover was movably disposed between the core and the outer cover. The size and shape of the outer cover defined the outer dimensions of the seat cushion. A conduit extended through the inner cover and the outer cover and communicated at one end with the interior space of the inner cover and at the other end with the atmosphere. Finally a valve was disposed in the conduit, the valve selectively opening and closing the communication between the interior of the inner cover and the atmosphere. The valve was operable by a person sitting on the cushion.
U.S. Pat. No. 5,137,329 patented Aug. 11, 1992 by G. G. Neale provided a user adjustable lumbar support for inclusion in a seat back. The support included rigid back plate having front and rear surfaces and which was adapted to extend vertically within a seat back. A front plate was included having a front and back surface and having an orthotic lumbar support contour at its front surface. A multi-chambered fluid actuator was provided including at least a pair of independently-inflatable chambers arranged vertically one chamber above the other. Means were provided to support the actuator and the front plate in assembled relationship to the back plate with the chambers between the plates. The supporting means were elastic to accommodate relative motion between the plates as the chambers were inflated and deflated. Means were provided for admitting and venting fluid under pressure separately to and from each of the chambers for selectively inflating and deflating the chambers to alter the positional relationship of the front plate to the back plate, so that the lumbar support contour can be adjusted by a person using the seat back to a position giving optimum lumbar support at a desired elevation along the seat back. Finally, resilient means were provided for supporting the back plate about a vertical axis of the seat back to allow compliant rotational motion of the support assembly within the seat back in response to like motion of the torso of a person seated against the seat back.
Portable cushions have also been provided to be usable in combination with existing seating. One such patented cushion is provided by U.S. Pat. No. 4,914,766 patented Apr. 10, 1990 by B. S. Moore. The patented pneumatic cushion included a bladder. Means were provided within the bladder which formed a plurality of hermetically-sealed cells. A charging valve was provided for admitting a pneumatic charge to one of the cells. A contour control valve was provided in another of the cells. Pneumatic communication means connected the control valve with each of the cells. The control valve had a first position for interconnecting the cells and a second position for pneumatically isolating the cells.
A commercially-available adjustable back cushion has been provided by Microcomputer Accessories Inc. That cushion was alleged to be able to be temporarily secured to the backrest of a chair. The cushion was said to be able to inflate or deflate the cushion to the natural contours of the back of the user.